Point taken, and the RAW get ignored (or at least forgotten every now and then), so my bad- but still...
Just to say it again, I like monsters that mess with the party- I realise Stunned is no fun but I also remember when we were playing the Pyramid of Shadows and the Warlord failed his saves and ended up Petrified- and nobody had the ritual/magic needed to undo the effect.
I understand I should tailor the scenarios to allow for player fun but there's part of me (the fiendish DM part) that enjoys it when a player gets his or her comeuppance for a little while, and with the right narrative, and as long as the players get on board, then I seem to be able to make it work.
The Warlord didn't roll another dice in the Pyramid of Shadows- he did come out of it a different player, with a whole new outlook, and he did some great roleplay when the PCs got him back to flesh again- it was his 40 days in the wilderness moment, Han Solo in the whatchamacallit. He came back a more spiritual player- Kane-like.
Just to add, I've been playing with this group of players via VTT for nearly two years- in all that time I have not killed one of their players, that's not for the want of trying. Previous to the Giant Frog I can't remember the last time any of them were Stunned, although I'm sure its happened- just very very rarely. I know what I can get away with the players- just every now and then I like to take a step over the line, just to remind them that there are nasty creatures out there (even at Level 1) that can make things difficult for them.
Again, fun = good, got it; it was fun for us, and after the Avenger got swallowed it made the rest of the fight a whole lot more interesting with PCs trying to rescue the guy, while avoiding the other frog- or else taking it down from range. But, of course, change the rules and/or omit as suits your purpose- not a problem.
Cheers Goonalan